Open AccessPlasmonic focusing of infrared SNOM tip patterned with asymmetric structures
Author(s) -
Qinbai Qian,
Haochi Yu,
Peng Gou,
Jie Xu,
Zhenghua An
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.012923
Subject(s) - optics , plasmon , materials science , surface plasmon polariton , near field scanning optical microscope , surface plasmon , grating , fano resonance , nanophotonics , curvature , surface plasmon resonance , dielectric , infrared , optoelectronics , nanotechnology , optical microscope , physics , nanoparticle , scanning electron microscope , geometry , mathematics
Several scattering type metal tips patterned with asymmetric metal/dielectric bump gratings are studied and proved to be efficient in focusing light energy into nano 'hot spot'. The dielectric bump tip shows complex mechanisms including local geometric resonance, surface plasmon polariton (SPP) standing wave resonance and Fano effect in the near-field enhancement. Additionally, considering the practical situation, we also demonstrate that, for the case of bending tip surface, the grating coupling method for plasmonic nano-focusing is still applicable if the intervals between neighboring bumps are well designed according to the surface bending curvature. With practical realizations, our results could benefit not only infrared scanning near-field optical microscopes (SNOMs) but also many other applications in nanotechnology such as sensing and lithography.